Multiple needle electrode device for electrostatic recording

ABSTRACT

TO FACILITATE THE INTRODUCTION OF INPUT SIGNALS TO THE INPUT TERMINALS. SIGNALS SUPPLIED TO THE SIGNAL INTRODUCING SECTION CAN BE RECORDED ON AN ELECTROSTATIC RECORDING SHEET BY THE RECORDING HEAD AT GREATER SPEED AND WITH IMPROVED RESOLUTION.   A MULTIPLE NEEDLE ELECTRODE DEVICE COMPRISING AT LEAST ONE SIGNAL INTRODUCING SECTION INCLUDING A NUMBER OF INPUT TERMINALS ARRANGED IN A CIRCLE, A RECORDING HEAD HAVING A NUMBER OF ELECTRODES ADJACENTLY ARRANGED IN TWO ROWS WITH THE ELECTRODES OF THE TWO ROWS BEING DISPOSED IN STAGGERED RELATIONSHIP SUCH THAT THE ELECTRODES OF ONE ROW ARE DISPOSED ADJACENT THE SPACES BETWEEN THE ELECTRODES OF THE OTHER ROW, AND A NUMBER OF LEAD-IN CONDUCTORS CONNECTING THE INPUT TERMINALS TO THE RESPECTIVE ELECTRODES. THE ELECTRODES, CONDUCTORS AND TERMINALS MAY BE MOUNTED ON ONE OR MORE INSULATING BASE BOARDS WHOSE PORTIONS MAY BE TWISTED INTO VARIOUS CYLINDRICAL SHAPES

United States Patent 91 Kusano et al.

[111 3,836,981 [4 Sept. 17, 1974 MULTIPLE NEEDLE ELECTRODE DEVICE FOR ELECTROSTATIC RECORDING Inventors: Haruo Kusano, Yokohama;

Norisada Takeuchi, Ksaukabe, both of Japan [73] Assignee: KabushikiKaisha Ricoh,

Tokyo,Japan Filed: May 10, 1972 Appl. No.: 251,907

[30] Foreign Application Priority Data [56] References Cited UNITED STATES PATENTS 11/1971 Shebanow et al..... 346/74 ES 10/1971 Blumenthal 346/74 ES 3/1970 Starr 340/324 AD 4/1971 Ohno et a1. 346/74 ES 9/1969 Yamamoto 346/74 ES X 9/1969 Starr 346/74 ES 3,235,874 2/1966 Boyd et al. 346/74 P 3,569,982 3/1971 Shebanow et al. 346/74 ES 3/1972 Brown 346/74 ES [57] ABSTRACT A multiple needle electrode device comprising at least one signal introducing section including a number of input terminals arranged in a circle, a recording head having a number of electrodes adjacently arranged in two rows with the electrodes of the two rows being disposed in staggered relationship such that the electrodes of one row are disposed adjacent the spaces between the electrodes of the other row, and a number of lead-in conductors connecting the input terminals to the respective electrodes. The electrodes, conductors and terminals may be mounted on one or more insulating base boards whose portions may be twisted into various cylindrical shapes to facilitate the introduction of input signals to the input terminals. Signals supplied to the signal introducing section can be recorded on an electrostatic recording sheet by the recording head at greater speed and with improved resolution.

5 Claims, 16 Drawing Figures 11 II II II [I ll. II II rl ll\ 1 \1 22 mgmmsar 1 119 4;

- saw a or 2 BACKGROUND OF THE INVENTION This invention relates to multiple needle electrode devices, and more particularly to a multiple needle electrode device for electrostatic recording which has particular utility in recording transmitted signals on an electrostatic recording sheet as in a facsimile system.

An electrostatic recording sheet E may consist, as shown in FIG. 1, of a base layer 1 made of paper prepared by mixing an electrically conductive material, such for example as carbon powder or metal powder, or a hygroscopic material or materials, such for exam ple as water glass and/or magnesium chloride and having an electric resistance in a range of 10 to 10 ohm-cm., and a dielectric layer 2 made of a copolymer of vinyl chloride and vinyl acetate, acrylic resin, methacrylic resin, or a mixture of such resins, or such resins containing titamiu moxide and/or barium titanate and having an electric resistance of over 10 ohm-cm. Alternatively, the sheet Emay consist, as shown in FIG. 2, of an ordinary paper of synthetic resin sheet 3, an electrically conductive organic material layer 4 made as of a polymer of vinyl benzil and a quaternary ammonium compound, and a dielectric layer 5 similar to layer 2. I Such an electrostatic recording sheet E may be electrically charged bydifferent systems. One of such systems isshown in FIG. 3 in which a grounded electrode plate 6 is arranged on the rear side of sheet E while an electrode ,7 connected to a positive high voltage source is arranged opposite on the front side'of sheet E. In the system shown in FIG. 4, a grounded electrode plate 8 is arranged on the side of dielectric layer 2 while an electrode 9 connected to a negative high voltage source is arranged opposite on the rear side of sheet'E. In still another system, an electrode 10 connected to a positive high voltage source is arranged on the side of dielectric layer 2 while an electrode 11 connected to a negative .high voltage source is arranged opposite on the rear side of sheet E as shown in FIG. 5. In these systems, voltages are impressed on the sheet in accordance with the signals received through one of the electrodes. In all the systems described, the electrode may be maintained in intimate contact with dielectric layer 2 or the two may be spaced apart from each other a small distance.

If dielectric layer 2 or 5 is electrically charged in the form of an original copy, an electrostatic latent image will be formed on electrostatic recording sheet E which may bedeveloped and converted into a toner image or visible copied image of the original by wet or dry developing methods such as the electrofax or xerographic .systems. If desired, a developing method using two baths of developing liquids may be used in rendering the electrostatic latent image visible. 1

For successively rocording incoming signals on electrostatic recording sheet E in a facsimile receiver to produce a facsimile record of the'original copy, an electrode device as shown in FIG. 6 has hitherto been used. The electrode device shown in the figure comprises a recordinghead composed of a number of electrodes 13 arranged in a'row or straight line on thedielectric layer 2 of an electrostatic recording sheet E. The sheet E is placed on grounded electrode plate 12 with the row of electrodes being confined within the width of the electrostatic recording sheet. Electrodes 13 are connected through conductors 14 to a signal input section 15 in which input terminals 16 of conductors 14 are arranged in a circular manner so that incoming signals are successively distributed to the input terminals 16 of the conductors by an incoming signal distributor 17 in the form of a brush having a distributor terminal 17a and adapted to rotate about the center of the circle. By using this type of electrode device,

electrostatic latent image points V as shown in FIG. 7 are formed in successive parallel rows as the incoming signals are distributed while electrostatic recording sheet E is continuously or intermittently moved.

Electrodes l3, conductors l4 and terminals 16 may be made of copper wires which are printed on a board forming a base which may be either a flexible insulating plastic sheet or an aluminum plate having opposite surfaces treated to be insulating. The electrodes 13 are formed in thin needle shape, so that the device is generally referred to as a multiple needle electrode device.

This is one example of a multiple needle electrode device in which the input terminals 16 are arranged circularly in a horizontal plane and distributor terminal 17a is rotated in the plane to distribute signals to the input terminals 16. However, alternate constructions of the signal introducing section may comprise making a portion of the insulating board forming the base in which input terminals 16 are disposed in cylindrical form so that distributor terminal 17a of signal distributor 17 may be rotated in a vertical plane, or arranging input tenninals 16 in a row or straight line with the distributor terminal being moved along such row of input terminals to distribute signals.

FIG. 7 shows electrostatic recording sheet E in a fragmentary enlarged view. It will be seen that, when signals are successively distributed to input electrodes 16,

electrostatic latent image points V are formed successively on electrostatic recording sheet E as the latter is moved in the direction of an arrow a. An electrostatic latent image is formed by such discrete electrostatic latent image points V. The density of such electrostatic latent image is increased and the resolving power of the facsimile receiver is improved by minimizing the spacing P between points V in the same row and the spacing P between rows.

It will be seen in FIG. 6, that the electrodes 13 of the prior art multiple needle electrode devices have been arranged in a row, so that difficulty has arisen when attempts are made to reduce the spacing between the electrodes 13 in order to reduce the spacing between points V in the same row. That is, it has been physically SUMMARY OF THE INVENTION This invention provides an improved multiple needle electrode device comprising a recording head having a number of electrodes arranged in two rows or straight lines with an insulating base board therebetween, the

two rows of electrodes being disposed in staggered relationship such that the electrodes of one row are positioned adjacent the spaces between the electrodes of the other row; and a signal introducing section comprising a number of input terminals arranged in a circle, with the electrodes and the input terminals being connected together by cylindrically arranged lead-in conductors.

Accordingly, the provision of the electrodes in two rows arranged in staggered relationship permits the spacing between the electrodes to be minimized while the electrodes are electrically insulated from one another. As a result, the spacing between the electrostatic image points constituting a facsimile record of the original copy on an electrostatic recording sheet is minimized, thereby increasing the density of the facsimile record and improving the resolving power of the facsimile receiver;

The provision of the signal introducing section comprising input terminals arranged in a circular form and connected to cylindrically arranged lead-in conductors facilitates distribution of incoming signals from a distributor terminal. Besides, the arrangement of the input terminals in this form of signal introducing section eliminates the disadvantage of the prior art devices of becoming useless when the terminals undergo wear by permitting corrective adjustment rather than replacement. According to this invention the device has a long service life because the input terminals can be used without any trouble even if they undergo wear.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 and FIG. 2 are sectional views showing conventional electrostatic recording sheets;

FIG. 3, FIG. 4 and FIG. 5 are sectional views showing different conventional manners in which an electrostatic recording sheet is electrically charged:

FIG. 6 is a sectional view showing the manner in which a multiple needle electrode device of the prior art receives incoming signals from a distributor;

FIG. 7 is a fragmentary enlarged plan view of an electrostatic recording sheet showing by way of illustration electrostatic latent image points formed thereon by means of a conventional multiple needle electrode device.

FIG. 8 is an end view of one form of the recording head of the multiple needle electrode device according to this invention;

FIG. 9 is a fragmentary enlarged plan view of an electrostatic recording sheet showing electrostatic latent image points formed thereon by means of the multiple needle electrode device according to this invention;

FIG. 10 is an end view of an alternate form of the recording head of the multiple needle electrode device according to this invention;

FIG. 11 is an end view of one form of the signal input section of the multiple needle electrode device according to this invention in which the signal introducing section is in cylindrical form and one row of electrodes is arranged on the outer surface of the cylinder while the other row of electrodes is arranged on the inner surface thereof, with a signal distribution system suiting this form of signal introducing section being shown in operation;

FIG. 12 is a perspective view of another embodiment of this invention in which the signal introducing section is formed in dual cylinder form and one row of electrodes is arranged on the inner surface of one cylinder while the other row of electrodes is arranged on the inner surface of the other cylinder;

FIG. 13 is an end view of the signal introducing section of the embodiment of FIG. 12, showing a signal distribution system suiting this form of signal introducing section being shown in operation;

FIG. 14 is a perspective view of a further embodiment of a signal introducing section in accordance with this invention;

FIG. 15 is an end view of the signal introducing section of the embodiment of FIG. 14,.showing a signal distribution system suiting this form of signal introducing section; and

FIG. 16 is a plan view of the insulating base board formed with a slot therein.

DESCRIPTION OF PREFERRED EMBODIMENTS The embodiments of the invention will now be described in detail with reference to FIG. 8 through FIG 16.

In FIG. 8, a row of electrodes 18 is arranged on one surface of an insulating base board 18 while another row of electrodes 20 is arranged on the other surface thereof. The two rows of electrodes 19 and 20 are disposed in staggered relationship so that the electrodes of one row are disposed adjacent the spaces between the electrodes of the other row to form a recording head H. The arrangement of the electrodes as aforementioned permits a spacing P1 between electrostatic latent image points V formed on electrostatic recording sheet E to be minimized as shown in FIG. 9, though a spacing Po between the electrodes of the same row cannot be reduced below an allowable minimum. Thus, it is possible to increase the density of a facsimile record of the original copy and improve the resolving power of the facsimile receiver. 'That is, this invention permits the resolving power of a facsimile receiver from the level of 4 lines per millimeter of the prior art to that of over 8 line per millimeter. Preferably, the thickness of insulating base board 18 is reduced as much as possible. It has been ascertained that the thickness can be reduced to the order of 30 microns in actual practice.

In FIG. 10, an alternate recording head H comprises a row of electrodes 21 arranged on one surface of one insulating base board 22 and another row of electrodes 21 arranged on one surface of another insulating base board 22; one electrode carrying base board being superposed on and attached to the other electrode carrying insulating board in such manner that the electrodes of the two rows are arranged in staggered relationship with the electrodes of one row being disposed adjacent the spaces between the electrodes of the other row.

The electrodes of the multiple needle electrode device according to this invention are connected through lead in conductors to a signal introducing section which may be constructed in the various forms as presently to be described. Preferably, the conductors are gathered together in one surface so that incoming signals may be distributed in the normal order to the respective input electrodes.

In FIG. 11, there is shown one form of signal introducing section for the multiple needle electrode device according to this invention which is formed in cylindrical form by folding an end portion of electrode carrying insulating base toward 18 opposite to the end portion at which recording head H with the needle electrodes isformed (FIG. 8). There is also shown an incoming signal distributor 25 of the rotary type suiting this form of signal introducing section. Such distributor 25 is provided with distributor terminals 23 and 24 which are arranged in face-to face relationship and adapted to come into engagement with input terminals 19a and 20a of the respective conductors to the needle electrodes successively to distribute incoming signals to the latter.

The manner of distributing incoming signals at an edge of the peripheral surface of the cylindrical signal introducing section as aforementioned offers many advantages. Distribution of signals is facilitated and since the signal distributor terminals move in sliding motion along the inner and outer peripheral surfaces of the cylindrical signal introducing section, the distributor terminals can be maintained in contact with the input terminals of the signal input section at all times by moving the former axially of the cylindrical signal introducing section when the latter undergo wear. This arrangement permitting corrective adjustment is more advan. tageous than the arrangement in which the input tenninals of the multiple needle electrodes are arranged in planar form, because in the latter case an arm supporting the distributor terminals must be extended as the input terminals of the signal introducing section undergo wear so that replacement is necessary. This advantage is also true of the embodiments subsequently to be described.

FIG. 12 shows another embodiment of the multiple needle electrode device according to this invention in which two rows of electrodes are arranged on an insulating base board in the manner of FIG. 10, and the end portions of the two insulating base boards, opposite to the end portions thereof at which the recording head H is formed, are each folded in a cylindrical form, so that the order of arrangement of the input terminals 21a of conductors 21b agrees with the order of arrangement of the electrodes 21 at the other ends of conductors 21b. FIG. 13 shows signal distributors 26 and 27 suiting the signal introducing sections of the type shown in FIG. 12, which signal distributors are adapted to rotate in synchronism with each other so as to distribute incoming signals to the input terminals 21a in the normal order. Any known means may be used for synchronizing the two signal distributors 26 and 27 with each other. For example, pulleys 28 and 29 and a timing belt 30 may be used as shown to attain the end.

FIG. 14 shows another embodiment of the multiple needle electrode device in accordance with the arrangement in FIG. of this invention, in which an end portion of one of the insulating base boards 22, opposite to the end portion thereof on which the recording head electrodes 21 are provided, is twisted about the longitudinal center axis of the base board through 180 and shaped into a semi-circular form, while the end portion of the other insulating base board opposite to the recording head end portion is also shaped into a semi-circular form, so that the two semi-circular end portions of the insulating base boards can be joined into a cylindrical form with the input terinals 21a disposed thereon.

Now, assuming that in the embodiment of FIG. 14 the electrodes of one row of recording head H are arranged in the order 1, 3, 5 while the electrodes of the other row thereof are arranged in the order 2, 4, 6 the input terminals 21a of the signal introducing tribution poles 31 and 32 adapted to rotate about the longitudinal center axis of the cylindrical signal introducing section is used to distribute signals to the electrodes in the normal order 1, 2, 3, 4. With this embodiment, a signal distributor of simple construction can be used for distributing incoming signals readily and positively.

The provision of a slot 34 in substantially the central portion of the insulating base board 22 which is twisted, with the major portion of the slot being aligned with the longitudinal axis of the base board, facilitates the operation of twisting the insulating base board. Such a slot may be formed in any number and at any position as desired.

What we claim is:

l. A multiple needle electrode device comprising:

a. at least one signal introducing section including a plurality of input terminals;

b. a recording head, including a plurality of electrodes corresponding in number to said input terminals and arranged in two adjacent rows with the electrodes of the two rows being disposed in staggered relationship, such that the electrodes of one row are disposed adjacent the spaces between the electrodes of the other row;

c. a plurality of lead-in conductors each connecting one of said plurality of input terminals to one of said plurality of electrodes and d. two insulating baseboards, each having two opposite ends with one of said rows of electrodes arranged on one end and the input terminals connected thereto arranged correspondingly in a row on the other end with the corresponding lead-in conductors extending one side therebetween, one of said two insulating baseboards having its input terminal end portion twisted about the longitudinal axis of said baseboard through and shaped into a semi-circular form, and the other of said two insulating baseboards having its input terminal end portion shaped into a semicircular form and joined with the semicircular end of said twisted insulating baseboard into a cylindrical form, so that the order of arrangement of the electrodes in their row on one end of the twisted insulating baseboard and the order of arrangement of the corresponding input terminals on the other end are reversed.

2. A device as in claim 1 further comprising a signal distributor means for rotating about an axis at the center of the circle formed by the joined semicircular ends of said insulating baseboards and sequentially contacting said input terminals.

3. A device as in claim 1 wherein at least one elon- Y gated slot is formed substantially in the central portion of the twisted insulating base board, said slot being disposed with its major axis aligned with the longitudinal axis of the twisted insulating base board.

4. A device as in claim 1 wherein the thickness of the insulating baseboards is of the order of 30 microns.

5. A device as in claim 1 further comprising an additional plurality of input terminals and an additional plurality of electrodes corresponding in number to said additional input terminals and arranged in adjacent rows with the electrodes of the two rows being disposed in 7 8 staggered relationship and an additional plurality of opposite one of said rows of electrodes and the addilead-ln Conductors, each connectmg one of sald addl' tional lead-in conductors extending between the other tional plurality of input terminals to one of said additiOnal plurality of electrodes, the additional lead-in faddmnal electmesandthe cmespmdmg conductors extending between one row of additional ditional input terminals on the Side Ofthe other insulat' electrodes and the corresponding additional input termg base-board pp the other row of electrodesminals on the side of one of said insulating baseboards 

